Unix - 使用 shell 腳本的簡單計算器 [已編輯]

Question

我剛開始在 Unix 操作系統中使用 shell 編寫一個簡單的腳本，我嘗試先編寫一個簡單的計算器代碼，該代碼讓用戶選擇一個操作（加法、減法等），它將被保存為一個變量（選擇）然后，讓用戶插入任意兩個數字，這些數字將被保存為變量（num1 和 num2） 最后，執行操作，檢查代碼以獲取更多信息

echo "+--------------------+"
echo "| Simple Calculator  |"
echo "+--------------------+"
echo "This shell is a simple calculator that takes two numbers from user, perform math operation then return the results"
echo Please choose an operation from the following:
echo 1,Addition
echo 2,Subtraction
echo 3,Multiplication
echo 4,division
echo Please choose an operation
read choice
echo Please insert the 1st number:
read num1
echo Please insert the 2ed number:
read num2
case $choice
1) echo "The result of addition operation is:`expr $num1 + $num2`;;
2) echo The result of Subtraction operation is:`expr $num1 - $num2`;;
3) echo The result of Multiplication operation is:`expr $num1 \* $num2`;;
4) echo The result of Division operation is:`expr $num1 \/ $num2`;;
*) echo invalid operation, please try again;;
esac

不幸的是，即使我做了一些更改，代碼仍然無法正常工作，它一直顯示此錯誤：

./shell.sh: line 16: syntax error near unexpected token 1'./shell.sh: line 16: 1) echo 加法運算結果為： expr $num1 + $num2 ;;'

注意：此代碼不適用於大學項目，也不適用於我探索和學習的家庭作業。

Answer 1

您的case語法錯誤。

http://tldp.org/LDP/Bash-Beginners-Guide/html/sect_07_03.html

解釋如何用case ； 因為你想做的事情並沒有從你的源代碼中變得清晰，所以我真的不能給你太多關於如何做的信息:(

Answer 2

為了娛樂：

#!/bin/bash
echo "Better calculator"
while read -r -p 'Enter expression (CTRL-C or CTRL-D for end)> ' exp
do
    echo "$exp =" $(bc -l <<< "$exp")
done

或者直接輸入命令提示符：

bc -l

但可能你的老師想要不同的東西...... :)

Answer 3

所以我現在知道我的錯誤了：D

我的錯誤在第 15 行，我應該在選擇后輸入“in”

"case $choose in" --> 這在你使用 "case" 時非常重要

簡單吧！ --> 這讓我瘋狂了一陣子"^__^

Answer 4

echo "+--------------------+"
echo "| Simple Calculator  |"
echo "+--------------------+"
echo "This shell is a simple calculator that takes two numbers from user, perform math operation then return the results"
echo Please choose an operation from the following:
echo 1,Addition
echo 2,Subtraction
echo 3,Multiplication
echo 4,division
echo Please choose an operation
read choice
echo Please insert the 1st number:
read num1
echo Please insert the 2ed number:
read num2
case $choice
1) echo "The result of addition operation is:`expr $num1 + $num2`;;
2) echo The result of Subtraction operation is:`expr $num1 - $num2`;;
3) echo The result of Multiplication operation is:`expr $num1 \* $num2`;;
4) echo The result of Division operation is:`expr $num1 \/ $num2`;;
*) echo invalid operation, please try again;;
esac